Smoke pot cover



April 22, 1947. H. E. KRASNER AL 7 2,419,357

SMOKE POT COVER Filed Feb. 5, 1945 INVENTORJ'. 661/2010 .67 AeAwm-e AND BY @[Pf V4 AYAMf/V'z? nHJ 3W Patented Apr. 22, 1947 SMOKE POT COVER Harold E. Krasner and Bertha Klausner, New York, N. Y.

Application February 3, 1945, Serial No. 576,093

4 Claims.

The present invention is directed to devices such as smoke pots, and more particularly C tain structural features thereof.

Smoke pots have heretofore been made of a container usually of sheet steel or the like, having a steel cover thereon, said cover being perforated. "The pot is filled with suitable substances which by reaction produce smoke, the latter issuing from the openings in the steel cover. Such devices have been satisfactory in use, although it has been desirable to decrease the weight thereof and also the cost. Because of the use of steel covers, which had been considered necessary in order to provide the desired strength, the entire assembly was unduly heavy. In order to lock or hold the steel covers in place, additional elements were required, rendering the assembly relatively expensive. In order to provide theopenings in the steel covers, relatively expensive dies and tools were necessary for shaping and punching the steel sheets. This involved a considerable amount of labor and further increased the cost of the device. v

The present invention is intended and adapted to overcome the diiiiculties and disadvantages inherent in devices of the type described and to provide a smoke pot which is simple in construction, has but few parts and is inexpensive to produce.

It is also among the objects of the present invention to provide a structure of smoke pot which has a high degree of strength, which will withstand rough and careless handling and accidental shocks and which will require a minimum of labor in the production thereof.

It is still further among the objects of the present invention to provide a structure of a smoke pot which is highly suitable for quantity production, which requires a minimum ofdies and tools and in which expensive dies and tools are eliminated.

In practicing the present invention, there is provided a smoke pot having a container of the usual type, but in place of the steel cover there is provided a disk of special material treated by special means whereby said disk may be introduced into the smoke pot and held against accidental displacement by extremely simple means. The disk is preferably made of a plurality of very thin layers of loosely matted fibers, usually cellulose. These layers are impregnated with a mixture of suitable inorganic salts in relatively small amounts in order to impart fireproofing qualities to the matted fibers.- The several layers are consolidated under pressure so that they are blended into a unitary mass having high strength and in which the laminations are not apparent. This is essential for obtaining an adequate degree of strength, flexibility and toughness, required in the present invention.

The two faces of the disk are treated by pressure in the presence of moisture or Water 'on said surfaces, in order to render said surfaces dense and smooth, to close the pores, while leaving the body of the disk in relatively porous condition.

'The openings in the disk are then cut by-suitable dies which are of an inexpensive variety and a thin surface film or coating of a suitable synthetic resin is placed over the entire surface of the disk so as to seal the edges thereof and the openings therein. This prevents the accidental spewing of the salts and prevents the entrance of water, chemicals or the like, thereby preventing any distortion, separation or deterioration of the disk. Such a disk is resistant to shock, has a tough surface and is non-inflammable. It is capable of withstanding temperatures from 700 to 1000 F. and retains its strength both at low temperatures such as minus 40 F. and at high temperatures, around F. Under such conditions the disk doesnot crack or melt. strength is such that it may be dropped from a height of 300 to 400 it. without injury.

In the accompanying drawing constituting a part hereof and in which like reference characters indicate like parts.

Fig. 1 is a vertical cross-sectional view taken through a smoke pot provided with a disk made in accordance with the present invention;

Fig. 2 is a top plan view thereof; and

Fig. 3 is an enlargedvertical cross-sectional view taken through the disk showing particularly the impregnating of coating materials thereon.

The container or body I is made of any suitable material such as thin sheet steel and of usual form. Along the upper edge thereof is an annular recess 2 into which a disk 3 is forced. The disk is made of fibrous material and has a sufficient resiliency so that it may be forced into said recess without injury thereof.

The disk is provided with a series of relatively large openings 4 arranged in a circle and a smaller central opening 5. Within the body of disk 3 is a mixture 6 of inorganic salts imparting fireproofing qualities thereto. The upper and lower faces of disk 3 are provided with a thin film of a heat-hardened synthetic resin 1, said film extending around the edges 8 of openings 4 and 5 and also sealing the edge 9 of the disk. 1

In order to obtain the desired properties in The the disk, it is made by a special process. Paper or cellulose fibers are ground to the proper size and run into a vat containing a relatively large amount of water, which acts as a carrier for the resulting pulp. The mixture is beaten until a homogeneous mass is formed. The pulp is then allowed to flow onto the moving wires of a paper making machine and most of the water removed in the procedure,

The material is then carried under a spray from which a solution of certain inorganic salts is introduced uniformly into the material. In the preferred embodiment, the solution contains a mixture of equal parts of ammonium phosphate and sodium tetraborate. The amount of solution used is such that the salts constitute from 2% to 7% by weight of the finished disk.

The loosely matted fibers in sheet form are wound around a revolving cylinder and a suitable number of layers of the sheet material is formed thereon. After the desired thickness has been obtained, the material is slit, removed from the cylinder and placed in a mold where hydraulic pressure is applied, reducing the thickness of the material substantially, at the same time removing most of the water therein.

The sheet so formed is then dried slowly in a kiln over a relatively long period of time, usually around twenty-four hours. The temperature is gradually increased so as to cause slow evaporation of the water, thereby resulting in a product.

having high strength and toughness. All danger of warping is prevented by this treatment.

The sheets so formed are then wetted with a small amount of water which is allowed to wet the faces only of the sheet. Then it is subjected to heat and pressure in steel calender rolls, which causes some compression of the sheet, most of said compression being at the surfaces only. This tends to close the pores on the surface and render the sheet waterproof and resistant to chemical action.

The sheet is then out and punched by dies which are inexpensive, whereby the various openings in the sheet to form disks are provided. Preferably the disks are further treated by spraying with a solution of a phenol formaldehyde condensation product which is resinous in nature and is dissolved in suitable organic solvents. A thin film of such a resinous material is formed on the disks, said film being continuous and homogeneous and coating not only the faces of the disk but also the edge and the walls of the openings. The solvents are evaporated and the disks heated to a sufficient temperature for a sufficient time to cause the resin to set and become permanently infusible and insoluble. Such a coating further-enhances the resistance of the disks to chemical action. It also completes the sealing of the disks against infiltration of liquids.

The present invention has numerous advantages. The spraying or otherwise coating of the resin after the fabrication of the disk is completed gives a strong disk and one which is flexible and is resistant against chipping and cracking. The raw edges produced by the fabrication are sealed by the resin.

The punching operation being conducted before the resin is applied allows inexpensive dies to be used instead of alloy steel. It also permits production at a high rate. The resiliency of the disk allows it to be forced into the smoke pot and causes the disk to fit firmly in the desired position.

The specific treatment of the material to form the disk gives a high degree of resiliency, strength and toughness, so that it is capable of Withstanding rough handling and accidental shocks. The disk is impervious to the chemical action of smoke and the chemicals used in producing the same. It is also resistant to rain and sleet and salt water. It withstands high temperatures and can resist direct contact with flame up to temperatures of 1000 F. It does not become brittle in sub-zero weather and is resistant against all conditions of weather which may be met with. A pot provided with a disk of the present invention is much lighter in Weight than those of the prior art and is easily transported and handled.

Although I have described the invention setting forth a single embodiment thereof, many variations in the details may be made within the spirit of the invention. For instance, the openings 4 and 5 may be cut before the calendering operation, whereby the dies last longer, Also, the waste material not having been consolidated may be re-worked into pulp mixed with fresh material. In addition to the salts named above, other ammonium and sodium salts of inorganic acids may be incorporated, such as titanate, sulphate and silicate. It may be possible to partly or completely substitute such salts for those specifically named above. It is essential, however, that there be a mixture of ammonium and sodium salts as fireproofing agents.

These and other variations in the details of the invention may be made within the scope thereof and the invention is to be broadly construed and not to be limited except by the character of the claims appended hereto.

We claim:

1. A top for a smoke pot comprising a fiat disk, a plurality of openings in said disk, said disk consisting of a plurality of thin layers of loosely matted cellulose fibers, said layers having dispersed therein a mixture of ammonium phosphate and sodium borate in substantially equal proportions, the amount of said salts being from 2% to 7% by weight of said disk, said layers being compressed and interlocked into a unitary mass, the upper and lower faces only of said disk being dense and smooth and free from pores, the central portions of said disk being relatively porous, said disk having a thin surface coating of water and weather-resistant synthetic phenol-formaldehyde resin free from filler and plasticizer, said coating being permanently infusible and insoluble, said resin filling the pores in said surface to prevent spewing of said salts, said coating sealing the edges of said disk and. said openings, said disk being strong, resistant to shock, resilient, having a tough surface, and being non-inflammable, the thickness of said disk being less than 1% of the diameter thereof and the specific gravity being less than 1.

2. A method of making a top disk for smoke pots which comprises forming a plurality of superimposed layers of loosely matted cellulose fibers, uniformly impregnating said layers with a solution of a mixture of ammonium phosphate and sodium borate in equal proportions, the amount of said salts being from 2% to 7% by weight of said disk, subjecting said layers to pressure to blend the same into a unitary mass, kiln drying the same to remove the water therefrom, then wetting the faces of said mass with water and subjecting the same to heat and pressure by calendering to close the surface pores thereof and leave the central portions relatively porous, cutting openings in the disk so formed, thereafter coating said disk with a solution of phenol-formaldehyde resin to coat the faces and edges thereof and the walls of said openings, and heating said disk to permanently harden said resin.

3. A method of making a top disk for smoke pots which comprises forming a plurality of superimposed layers of loosely matted cellulose fibers by winding a sheet of said fibers around a cylinder to provide a plurality of layers, slitting,

said material, subjecting the same to hydraulic pressure to reduce the thickness thereof and remove water therefrom, uniformly impregnating said layers with a solution of a mixture of ammonium phosphate and sodium borate in equal proportions, the amount of said salts being from to 7% by weight of said disk, subjecting said layers to pressure to blend the same into a unitary mass, kiln drying the same to remove the water therefrom, then wetting the faces of said mass with Water and subjecting the same to heat and pressure by calendering to close the surface pores thereof and leave the central portions relatively porous, cutting openings in the disk so formed, thereafter coating said disk with a solution of phenol-formaldehyde resin to coat the faces and edges thereof and the walls of said openings, and heating said disk to permanently harden said resin.

4. A method of making a top disk for smoke pots which comprises forming a plurality of superimposed layers of loosely matted cellulose fibers by winding a sheet of said fibers around a cylinder to provide a plurality of layers, slitting said material, subjecting the same to hydraulic pressure to reduce the thickness thereof and remove water therefrom, uniformly impregnating said layers with a solution of a mix- 6 ture of ammonium phosphate and sodium borate in equal proportions, the amount of said salts being from 2% to 7% by weight of said disk, subjecting said layers to pressure to blend the same into a unitary mass, kiln drying the same to remove the water therefrom by slowly drying the same for about 24 hours at gradually increasing temperatures to evaporate the water and to prevent warping of said mass, then wetting the faces of said mass with water and subjecting the same to heat and pressure by calendering to close the surface pores thereof and leave the central portions-relatively porous, cutting openings in the disk so formed, thereafter coating said disk with a solution of phenol-formaldehyde resin to coat the faces and edges thereof and the walls of said openings, and heating said disk to permanently harden said resin.

HAROLD E. KRASNER. BERTHA KLAUSNER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS, 

